Using the Snowflake on CentOS portion of the Adobe Campaign Snowflake install guide ( https://docs.adobe.com/content/help/en/campaign-classic/using/getting-started/accessing-external-dat...) I have installed snowflake on our Adobe Campaign unix host.
When the windows client console is started and connected to the test instance, snowflake does not appear as a type under external database when creating a new external account.
The install completed normally and the server has been restarted, there no additional configuration instructions.
Were you able to resolve this? Was it actually the build upgrade issue? Do let us know in case it's not and you need more help.
Snowflake is available from ACC Release 20.1 - Build 9122. Check your build, you may need to upgrade it.